JP2829475B2 - Radio paging receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio paging receiver in a radio paging system. In particular, the present invention relates to a radio paging receiver used in a radio paging system in which a paging signal is error-correction-coded and the paging signal is transmitted a plurality of times. The paging signal includes a case where a message corresponding to the individual number is included in the paging signal in an individual number which is an address for specifying each radio paging receiver.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing a radio paging receiver. The radio paging receiver includes a radio unit 1 that receives a radio paging signal from a base station, a waveform shaping unit 2 that shapes a waveform, a decoder 3 that decodes a paging signal, and a number that stores an individual number of the radio paging receiver. The ROM 5 is compared with the individual number stored in the number ROM and the individual number of the decoded call signal, and when they match, a ring tone is output to the speaker 7 and the decoded message is displayed on a display such as a liquid crystal display. (L
CD) 6 is provided.

[0003] The operation will be described. The ringing signal received by the radio section 2 and the waveform shaping section 2 is subjected to error correction decoding by a decoder 3. When the error correction decoding is correctly performed, the collation unit 4 compares and compares the receiver address stored in the number ROM 4 with the output of the decoder 3. A signal is displayed. When the message signal is decoded correctly following the address signal, the message is displayed on the display 6. Here, the number of error correction bits t at the time of error correction decoding in the decoder 3 is predetermined and fixed.

FIGS. 9 to 11 show a receiving method up to three times of receiving a paging signal, and explain a decoding situation of the paging signal. FIG. 9 shows the decoding status of the signal received at the first s0 time. Here, it is assumed that the call signal is composed of eight error correction code words, and the number of error correction bits at the time of decoding the error correction code is 2 bits. In addition,
9 to 11, the third codeword is represented by # 3,
The code word of the first reception is represented as # 3-1, and the code word of the second reception is represented as # 3-2.

First, as shown in FIG. 9, the reception levels at the first s0 time are codeword # 2-1 and codeword # 5-
Near 1 there are two levels of dip. Since this is the first reception, all the codewords are to be decoded, and as a result of the decoding, the codeword #
It is assumed that 1-1, codeword 3-1 and codeword # 5-1 cannot be decoded correctly, and codeword # 2-1 has been decoded correctly but has an error in the codeword (hereinafter referred to as erroneous correction). . After that, the receiver does not decode the codewords that have already been correctly decoded, and only the codewords # 1, # 3, and # 5 are to be decoded.

Next, as shown in FIG. 10, the second s0 +
It is assumed that the reception level at the time T is one near the code word # 5-2, and accordingly, only the code word # 5 cannot be correctly decoded among the decoding targets. Here, T is a retransmission interval. Therefore, the subsequent decoding target is only codeword # 5.

Further, as shown in FIG. 11, the reception level at the third time s0 + 2T is good in the vicinity of codeword # 5-3, so it is assumed that codeword # 5 can be decoded correctly. Thereby, codeword # 1 to codeword #
8 can be decoded correctly.

In order to reduce the call delay, that is, the time from when a call is made to when a call is made,
Even if the number of times of reception is less than the maximum number of times, if the calling signal addressed to the receiver is recognized, the calling operation is executed. Executing the calling operation in the above-described example causes a problem that an error call or message is erroneously displayed due to an error remaining in the code word in code word # 2.

[0009]

In radio paging, reception is performed many times in order to improve the reliability of a received signal. As shown in the examples shown in FIGS. 9 to 11, the reception quality is poor. Under error correction decoding, there is a problem that the possibility of performing error correction increases.

Generally, there are two methods for suppressing erroneous correction. The first method is to increase the number of check bits constituting the error correction code to increase the distance between codes. However, this method has a disadvantage that the ratio of information bits is lower than the total number of bits, and the transmission efficiency is deteriorated. The second method is a method in which the number of error correction bits at the time of decoding an error correction code is not set to the maximum number of error correction bits possessed by the code word, but the number of correction bits is reduced and its capability is used for error detection. . However, this method has the drawback that the number of error correction bits is reduced, so that the number of cases where correct reception is not possible is increased and the codeword reception rate is reduced.

The present invention suppresses the occurrence of erroneous correction by reducing the number of correction bits in a poor environment such as a low reception level based on the reception quality at the time of receiving a code word. It is an object of the present invention to provide a radio paging receiver that can obtain good reception characteristics by operating to increase the number of correction bits and improve the reception rate under good quality.

[0012]

SUMMARY OF THE INVENTION A first aspect of the present invention is as follows.
A means for receiving a plurality of times of a paging signal obtained by error-correcting and encoding information including an individual address designating each called receiver, a decoding means for performing error-correction decoding of the received paging signal, and collating the decoding result. Display means for performing a call display when a call is made, wherein the decoding means includes means for changing the number of error correction bits at the time of error correction decoding according to reception quality. Features.

[0013] A means for monitoring the reception quality of a plurality of receptions is provided, and the number of error correction bits can be changed based on the monitoring result of this means.

[0014] A second aspect of the present invention is a case where diversity reception is performed, wherein a diversity receiving circuit is provided, and the decoding means performs the error correction bit number at the time of error correction decoding according to the number of reception combining branches of the diversity reception. Is included.

[0015]

According to the present invention, the number of error correction bits at the time of decoding by the decoding means is changed according to the reception quality. When the reception quality is poor, the number of correction bits is reduced. As a result, erroneous correction does not occur for a code word having poor reception quality, and decoding can be performed when a call signal is received with good reception quality next time, so that residual erroneous correction does not occur and a good reception rate is obtained. Can be. When a diversity receiving circuit is provided, control is performed so as to increase the number of correction bits in accordance with the number of receiving and combining branches.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of a radio pager according to a first embodiment of the present invention. This radio paging receiver includes a radio unit 8, a waveform shaping unit 2, a collating unit 4, a number ROM 5, a display 6, and a speaker 7,
As a feature of the present invention, an envelope detection output (R
A correction bit number variable decoder 9 that makes the number of correction bits variable based on SSI) is provided. Note that the variable correction bit number decoder uses a known correction bit number variable algorithm.

Next, the operation of the radio pager will be described.
The paging signal transmitted from the base station and received by the radio unit 8 and the waveform shaping unit 2 is decoded by the variable-correction-bits decoder 9. At this time, the variable number of correction bits decoder 9 obtains the reception quality of the code word to be decoded from the envelope detection output (RSSI) from the radio unit 8, controls the number of correction bits at the time of decoding, and performs decoding. I do. The correctly decoded signal is compared and collated by the collation unit 4 with an address signal stored in advance in the number ROM 5, and when both coincide with each other, a sound signal is transmitted to the speaker 7. When the calling signal has a message signal and is decoded correctly, the message is displayed on the display 6.

The operation of the present embodiment will be described with reference to FIGS.

In FIG. 2 to FIG. 4, the change point of the number of correction bits indicated by a broken line indicates a threshold value for changing the number of error correction bits with respect to the reception level. This indicates that the range can be changed.

First, as shown in FIG. 2, the reception level at the time s0 has two drops near the code words # 2 and # 5. In accordance with the fluctuation of the reception level, the number of error correction bits of each codeword is 1 bit in codewords # 2 and # 5, and is 2 bits in other codewords. 9 is controlled. Therefore, subsequent decoding targets are codeword # 1, codeword # 2, codeword # 3, and codeword # 5 that could not be decoded correctly. However, since the number of error correction bits is suppressed in a place where the reception level is poor, erroneous correction does not occur.

Next, as shown in FIG. 3, one drop in the reception level at the time s + T occurs near the code word # 5. The number of error correction bits set according to the reception level at the decoding target is 2 bits, 2 bits,
2 bits and 0 bits. The code word that is not correctly decoded by this is # 5. Also in this case, since the number of error correction bits is suppressed where the reception level is inferior, erroneous correction does not occur. A code word that could not be decoded correctly at the time s0 is correctly decoded by receiving many times because no erroneous correction has occurred.
As a result, the subsequent decoding target is only the code word # 5.

Further, as shown in FIG. 4, there is only one drop in the reception level at the time s + 2T, near code word # 3. The decoding target at the s + 2T time is the code word # 5, and the number of error correction bits set according to the reception level of this code is 2 bits. As a result, when the reception quality is poor, the effect of multiple receptions is expected to suppress the erroneous correction, and when the reception quality is good, the effect of the error correction is expected to improve the reception rate. Thus, codewords # 1 to # 8 are all decoded without error.

When the radio call receiver is configured as described above,
It is possible to eliminate a residual error due to erroneous correction occurring when a high reception rate is to be obtained by fixing the number of correction bits as in the related art, and a high reception rate can be maintained.

(Second Embodiment) FIG. 5 is a block diagram showing a configuration of a radio pager according to a second embodiment of the present invention. The radio paging receiver according to the second embodiment performs time diversity reception. A time diversity reception processor 10 is provided between the waveform shaping unit 2 and the variable correction bit number decoder 9 of the radio paging receiver shown in FIG. Is provided, and the variable number of correction bits decoder 9 is characterized in that the number of error correction bits is increased in accordance with an increase in the number of reception branches.

The operation will be described. The calling signal received by the radio unit 8 and the waveform shaping unit 2 is subjected to calculation by the time diversity reception processor 10 to perform time diversity processing. The variable bit number decoder 9 decodes the signal after the dime diversity processing. The correctly decoded signal is compared and collated by the collation unit 4 with an address signal stored in advance in the number ROM 5,
If they match, a sound signal is sent to the speaker 7. When the call signal has a message signal and is correctly decoded, it is displayed on the display 6.

The operation of the second embodiment will be described with reference to FIGS.

In time diversity reception, the reliability of each bit is improved by increasing the number of reception branches. For this reason, the number of error correction bits increases from 0, 1, 2,. . . Set so that As shown in FIG. 6, the reception level at time s0 has two drops near the code words # 2 and # 5. Since the number of error correction bits at s0 time is set to 0, the result of decoding by this is not correctly decoded in codeword # 1, codeword # 2, codeword # 3, codeword # 4 and codeword # 5. However, since the number of error correction bits is 0, no error correction is made.

Next, the reception level at s + T time is shown in FIG.
, There is one near codeword # 5. However, the reception level after combining by time diversity reception is shown in FIG.
As shown in (1), there is no drop in the reception level near the code word # 2, and the drop in the reception level is reduced as a whole. That is, the reception quality is improved by the time diversity reception process over the reception quality at the time s0. The actual reception quality is obtained for each bit by a method having a high reception level received at time s0 and time s0 + T. This method is one of the diversity receiving methods and is called selection diversity. The decoding targets at s0 + T time after the time diversity reception processing are codeword # 1, codeword # 2, codeword # 3, codeword # 4 and codeword # 5, and the number of error correction bits of these codewords is 1 Bit. Thereby, all codewords are correctly decoded.

As described above, when the reception quality is poor, the effect of multiple receptions is expected, and erroneous correction is suppressed. When the reception quality is good, the effect of error correction is expected, and the reception rate is improved. Code word # 1
Thus, codeword # 8 is correctly decoded without error.

[0031]

As described above, according to the present invention, since the number of correction bits is not fixed as in the prior art, it is possible to eliminate a residual error due to error correction occurring when a high reception rate is to be obtained. It is possible, and it is possible to maintain a high reception rate.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radio pager according to a first embodiment of the present invention.

FIG. 2 is a view for explaining a signal decoding state according to the first embodiment of the present invention.

FIG. 3 is a view for explaining a signal decoding state according to the first embodiment of the present invention;

FIG. 4 is a view for explaining a signal decoding state according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a radio pager according to a second embodiment of the present invention.

FIG. 6 is a view for explaining a signal decoding state according to the second embodiment of the present invention.

FIG. 7 is a view for explaining a signal decoding state according to the second embodiment of the present invention;

FIG. 8 is a block diagram showing a configuration of a conventional paging receiver.

FIG. 9 is a view for explaining a decoding state of a signal of a conventional paging receiver.

FIG. 10 is a view for explaining a signal decoding state of a conventional example paging receiver.

FIG. 11 is a view for explaining a signal decoding state of a conventional paging receiver.

[Explanation of symbols]

 1, 8 Radio unit 2 Waveform shaping unit 3 Decoder 4 Matching unit 5 Number ROM 6 Display (LCD) 7 Speaker 9 Correction bit number variable decoder 10 Time diversity reception processor

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04Q 7/00-7/38 H04L 1/00-1/20

Claims (3)

(57) [Claims] A means for receiving a plurality of times of a call signal obtained by error-correcting and encoding information including an individual address designating each called receiver; a decoding means for performing error-correction decoding of the received call signal; A display unit for performing a call display when a call is made by collating the decoding result, wherein the decoding unit changes the number of error correction bits at the time of error correction decoding according to reception quality. A radio paging receiver comprising means. 2. The radio paging receiver according to claim 1, further comprising means for monitoring the reception quality of said plurality of receptions, wherein the number of error correction bits is changed based on the monitoring result of said means. 3. A means for receiving a plurality of times of a call signal obtained by error-correcting and encoding information including an individual address designating each called receiver; a decoding means for performing error-correction decoding of the received call signal; A radio paging receiver comprising a display means for collating the decoding result and displaying a call when a call is made, comprising: a diversity receiving circuit; wherein the decoding means has an error according to the number of reception combining branches of the diversity reception. A radio paging receiver including means for increasing the number of error correction bits at the time of correction decoding.